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This work presents the results of removing heavy metals from paper mill wastewater (PMS) sludge spiked with cow dung (CD) employing Eisenia fetida. A total of seven set-ups were prepared: CD (100 percent), PMS: CD (1:3), PMS:CD (1:2), PMS:CD (1:1), PMS (100 percent), PMS:CD (3:1) and PMS:CD (2:1) and changes in chemical parameters were observed for 60 days. Vermistabilization caused the significant decrease in the level of Cd (32–37 percent), Cr (47.3–80.9 percent), Cu (68.8–88.4 percent), and Pb (95.3–97.5 percent) and substantial increase in EC, total-N, available P and K at the end. At the end, the tissues of inoculated worms showed the high load (mg kg−1, dry biomass) of Pb (8.81–9.69), Cd (2.31–2.71), Cr (20.7–35.9) and Cu (9.94–11.6), respectively which indicated bioaccumulation of metals by worms. The PMS:CD (2:1 and/or 3:1) appeared to be suitable waste mixture in terms of high metal removal and earthworm growth rates. Bioaccumulation, as quantified using BCF, was in the order: Cd>Cr>Pb>Cu. Results suggested vermiremediation as appropriate technology for bioremediation of heavy metals from PMS. [ABSTRACT FROM AUTHOR]

As the evidence of the toxic effects of bisphenol A (BPA) grows, its application in commercial products is gradually being replaced with other related compounds, such as bisphenol S (BPS). Nevertheless, very little is known about the occurrence of BPS in the environment. In this study, BPS was analyzed in 16 types of paper and paper products (n = 268), including thermal receipts, paper currencies, flyers, magazines, newspapers, food contact papers, airplane luggage tags, printing paper, kitchen rolls (i.e., paper towels), and toilet paper. All thermal receipt paper samples (n = 111) contained BPS at concentrations ranging from 0.0000138 to 22.0 mg/g (geometric mean: 0.181 mg/g). The overall mean concentrations of BPS in thermal receipt papers were similar to the concentrations reported earlier for BPA in the same set of samples. A significant negative correlation existed between BPS and BPA concentrations in thermal receipt paper samples (r = -0.55, p < 0.0001). BPS was detected in 87% of currency bill samples (n = 52) from 21 countries, at concentrations ranging from below the limit of quantification (LOQ) to 6.26 μg/g (geometric mean: 0.029 μg/g). BPS also was found in 14 other paper product types (n = 105), at concentrations ranging from 88%). To our knowledge, this is the first report on the occurrence of BPS in paper products and currency bills. [ABSTRACT FROM AUTHOR]

Semidefinite programs (SDPs) arising from the Kalman—Yakubovich—Popov (KYP) lemma are frequently encountered in systems robustness analysis, filter design, and other control/signal processing related applications. These programs possess a special structure that can be exploited to construct specialized algorithms that substantially outperform general-purpose SDP solvers. In this paper, a new interior path-following algorithm that utilizes this structure is proposed. The main idea behind the algorithm is a new barrier function for these specially structured SDPs. Convergence of the new algorithm is shown and a measure of the accuracy of suboptimal solutions produced by the algorithm is provided. The algorithm is tested in numerical experiments and the results indicate that the new algorithm is indeed favorable against general-purpose SDP solvers in many circumstances. [ABSTRACT FROM AUTHOR]

To enhance the impact resistance of penetration fuze, this paper investigates the response of fuze buffer materials to stress waves and develops a model for stress wave transmission inside the fuze. The stress concentration impacts of different cell structures of Imitation Bamboo Type Penetration Fuze Buffer Protection Structure (IBS) under stress wave action are compared and analyzed. The paper elucidates the impact of different cell parameters on stress concentration impacts, establishes nonlinear fitting functions of Stress Concentration Factor (SCF) and cell parameters, and solves the prediction error. Based on the wave function expansion method, an expression for Dynamic Stress Concentration Factor (DSCF) when stress waves interact with the potting material is derived, and numerical results of DSCF around bubbles under different physical parameters are provided. Finally, dynamic impact tests are conducted on the combined buffer scheme of penetration fuze. Impact test results show that, under an initial velocity impact of 50m/s, the overload peak attenuation rate is 39.42%, and under an initial velocity impact of 70 m/s, the overload peak attenuation rate is 32.87%. IBS can effectively protect the electronic components inside the fuze. [ABSTRACT FROM AUTHOR]

The framework of this paper was intertemporal choice, that is to say, the process whereby people were required to choose between a smaller-sooner reward and a larger-later income. In this study, the selection of rewards was supported by a discount function instead of direct preferences between the involved rewards. The objective of this paper was to measure the discounting concentration of a discount function through a variant of the Gini index and the Lorenz curve usually used in statistics. Both measures allowed for the comparison of the discounting concentration corresponding to two discount functions. The methodology employed in this paper was based on the parallelism between a discount function and the distribution function of an absolutely continuous random variable. This similarity allowed us to export the measures of concentration from the field of statistics to finance. The main result of this work was the analysis of the discounting concentration depending on other characteristics of the shape of a discount function (regularity and super-additivity) and the total area under the discount function curve. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to assess the hydrogen embrittlement sensitivity of carbon gradient heterostructure materials and to verify the reliability of the scratch method. Design/methodology/approach: The surface-modified layer of 18CrNiMo7-6 alloy steel was delaminated to study its hydrogen embrittlement characteristics via hydrogen permeation, electrochemical hydrogen charging and scratch experiments. Findings: The results showed that the diffusion coefficients of hydrogen in the surface and matrix layers are 3.28 × 10−7 and 16.67 × 10−7 cm2/s, respectively. The diffusible-hydrogen concentration of the material increases with increasing hydrogen-charging current density. For a given hydrogen-charging current density, the diffusible-hydrogen concentration gradually decreases with increasing depth in the surface-modified layer. Fracture toughness decreases with increasing diffusible-hydrogen concentration, so the susceptibility to hydrogen embrittlement decreases with increasing depth in the surface-modified layer. Originality/value: The reliability of the scratch method in evaluating the fracture toughness of the surface-modified layer material is verified. An empirical formula is given for fracture toughness as a function of diffused-hydrogen concentration. [ABSTRACT FROM AUTHOR]

Due to the climate effects and aviation threats of volcanic eruptions, it is important to accurately locate ash in the atmosphere. This study aims to explore the accuracy and reliability of training a neural network to identify cases of ash using observations from the Moderate Resolution Imaging Spectroradiometer (MODIS). Satellite images were obtained for the following eruptions: Kasatochi, Aleutian Islands, 2008; Okmok, Aleutian Islands, 2008; Grímsvötn, northeastern Iceland, 2011; Chaiteìn, southern Chile, 2008; Puyehue-Cordoìn Caulle, central Chile, 2011; Sangeang Api, Indonesia, 2014; and Kelut, Indonesia, 2014. The Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) was used to obtain ash concentrations for the same archived eruptions. Two back-propagation neural networks were then trained using brightness temperature differences as inputs obtained via the following band combinations: 12- 11, 11-8.6, 11-7.3, and 11 μm. Using the ash concentrations determined via HYSPLIT, flags were created to differentiate between ash (1) and no ash (0) and SO2-rich ash (1) and no SO2-rich ash (0) and used as output. When neural network output was compared to the test dataset, 93% of pixels containing ash were correctly identified and 7% were missed. Nearly 100% of pixels containing SO2-rich ash were correctly identified. The optimal thresholds, determined using Heidke skill scores, for ash retrieval and SO2-rich ash retrieval were 0.48 and 0.47, respectively. The networks show significantly less accuracy in the presence of high water vapor, liquid water, ice, or dust concentrations. Significant errors are also observed at the edge of the MODIS swath. [ABSTRACT FROM AUTHOR]

Introducing nanorods into a polymeric matrix can enhance the physical and mechanical properties of the resulting material. In this paper, we focus on understanding the dispersion and orientation patterns of nanorods in an unentangled polymer melt, particularly as a function of nanorod concentration, using molecular dynamics simulations. The system is comprised of flexible polymer chains and multi-thread nanorods that are equilibrated in the NPT ensemble. All interactions are purely repulsive except for those between polymers and rods. Results with attractive vs repulsive polymer–rod interactions are compared and contrasted. The concentration of rods has a direct impact on the phase behavior of the system. At lower concentrations, rods phase separate into nematic clusters, whereas at higher concentrations more isotropic and less structured rod configurations are observed. A detailed examination of the conformation of the polymer chains near the rod surface shows extension of the chains along the director of the rods (especially within clusters). The dispersion and orientation of the nanorods are a result of the competition between depletion entropic forces responsible for the formation of rod clusters, the enthalpic effects that improve mixing of rods and polymer, and entropic losses of polymers interpenetrating rod clusters. [ABSTRACT FROM AUTHOR]

Deformable gel particles (DGPs) possess the capability of deep profile control and flooding. However, the deep migration behavior and plugging mechanism along their path remain unclear. Breakage, an inevitable phenomenon during particle migration, significantly impacts the deep plugging effect. Due to the complexity of the process, few studies have been conducted on this subject. In this paper, we conducted DGP flow experiments using a physical model of a multi-point sandpack under various injection rates and particle sizes. Particle size and concentration tests were performed at each measurement point to investigate the transportation behavior of particles in the deep part of the reservoir. The residual resistance coefficient and concentration changes along the porous media were combined to analyze the plugging performance of DGPs. Furthermore, the particle breakage along their path was revealed by analyzing the changes in particle size along the way. A mathematical model of breakage and concentration changes along the path was established. The results showed that the passage after breakage is a significant migration behavior of particles in porous media. The particles were reduced to less than half of their initial size at the front of the porous media. Breakage is an essential reason for the continuous decreases in particle concentration, size, and residual resistance coefficient. However, the particles can remain in porous media after breakage and play a significant role in deep plugging. Higher injection rates or larger particle sizes resulted in faster breakage along the injection direction, higher degrees of breakage, and faster decreases in residual resistance coefficient along the path. These conditions also led to a weaker deep plugging ability. Smaller particles were more evenly retained along the path, but more particles flowed out of the porous media, resulting in a poor deep plugging effect. The particle size is a function of particle size before injection, transport distance, and different injection parameters (injection rate or the diameter ratio of DGP to throat). Likewise, the particle concentration is a function of initial concentration, transport distance, and different injection parameters. These models can be utilized to optimize particle injection parameters, thereby achieving the goal of fine-tuning oil displacement. [ABSTRACT FROM AUTHOR]

The exponential random graph model (ERGM) is a central object in the study of clustering properties in social networks as well as canonical ensembles in statistical physics. Despite some breakthrough works in the mathematical understanding of ERGM, most notably by Bhamidi, Bresler, and Sly [Ann. Appl. Probab. 21 (2011), pp. 2146–2170] through the analysis of a natural Heat-bath Glauber dynamics, and by Chatterjee and Diaconis [Ann. Statist. 41 (2013), pp. 2428–2461; Eldan [Geom. Funct. Anal. 28 (2018), pp. 1548–1596; and Eldan and Gross [Ann. Appl. Probab. 28 (2018), pp. 3698–3735] via a large deviation theoretic perspective, several basic questions have remained unanswered owing to the lack of exact solvability unlike the much studied Curie-Weiss model (Ising model on the complete graph). In this paper, we establish a series of new concentration of measure results for the ERGM throughout the entire sub-critical phase , including a Poincaré inequality, Gaussian concentration for Lipschitz functions, and a central limit theorem. In addition, a new proof of a quantitative bound on the W_1-Wasserstein distance to Erdős-Rényi graphs, previously obtained by Reinert and Ross [Ann. Appl. Probab. 29 (2019), pp. 3201–3229], is also presented. The arguments rely on translating temporal mixing properties of Glauber dynamics to static spatial mixing properties of the equilibrium measure and have the potential of being useful in proving similar functional inequalities for other Gibbsian systems beyond the perturbative regime. [ABSTRACT FROM AUTHOR]

In this paper, the values of the absolute constants in the Kolmogorov–Rogozin and Kesten inequalities are refined for the concentration function of the sum of independent random vectors in a Hilbert space. [ABSTRACT FROM AUTHOR]

This paper presents an easy to operate time-dependent, two-dimensional vertical model for the simulation of sand and mud concentrations, transport, and morphodynamic bed evolution in conditions with combined currents and waves. The basic model equation is the advection–diffusion equation for sediments including flow velocities, sediment mixing coefficients, and the settling velocity. The vertical distribution of the sediment mixing coefficient is described by fairly simple and flexible expressions based on flow and wave parameters with user-specified coefficients for calibration of results. The settling velocity is constant or dependent on the sediment concentration to represent mud flocculation and hindered settling processes based on input parameters. The bed boundary condition is modeled by a bed concentration as a function of the bed-shear stress due to currents and waves. The model is valid for sand concentrations and for low and high mud concentrations including fluid mud concentrations. The numerical SUSTIM2DV model has been used to simulate sand and mud transport and bed level changes in dredged (shipping) channels. The model is valid for perpendicular and oblique flow across a dredged channel. The channel slopes should not be too steep (1V:7H or milder), because logarithmic velocity profiles are used. Results of various validation cases of channel deposition of sand, silt, and (fluid) mud in tidal conditions with and without waves are presented. The effect of channel geometry is specifically addressed. The numerical model has also been used to derive sediment trapping factors, which can be used in simpler channel deposition models. [ABSTRACT FROM AUTHOR]

In this paper, tetrahedral amorphous carbon (ta-C) coatings containing Al were deposited by a hybrid technique of sputtering and arc evaporation. The influence of Al incorporation in the structure and properties of the ta-C coatings were studied as a function of the Al concentration. It is found that Al tends to form a Al-O-C bond when the Al concentration is small. An Al-C bond was detected when the Al concentration is high. Al can facilitate the graphitization of the ta-C coatings and the graphite cluster size as well as the sp2/sp3 ratio of the coatings increase as the Al concentration increases. The decline of the sp3 fraction causes the drop in the hardness of the coatings. The incorporation of Al can effectively decrease the residual stress of the ta-C coatings. During friction tests, Al can facilitate the formation of the sp2-rich graphitic tribo-layer and decrease the friction coefficient. Nevertheless, the decline of the hardness due to the Al incorporation will result in the increase in the wear rate of the coating. It is believed that the ta-C coating with a proper concentration of Al appears to achieve a good comprehensive performance with high hardness, low residual stress, and a low friction coefficient and wear rate. [ABSTRACT FROM AUTHOR]

Chemical-reaction optimization not only increases the yield of chemical processes but also reduces impurities and improves the performance of the resulting products, contributing to important innovations in various industries. This paper presents a novel barycentric kernel for chemical-reaction optimization using Bayesian optimization (BO), a powerful machine-learning method designed to optimize costly black-box functions. The barycentric kernel is specifically tailored as a positive definite kernel for Gaussian-process surrogate models in BO, ensuring stability in logarithmic and differential operations while effectively mapping concentration space for solving optimization problems. We conducted comprehensive experiments comparing the proposed barycentric kernel with other widely used kernels, such as the radial basis function (RBF) kernel, across six benchmark functions in concentration space and three Hartmann functions in Euclidean space. The results demonstrated the barycentric kernel's stable convergence and superior performance in these optimization scenarios. Furthermore, the paper highlights the importance of accurately parameterizing chemical concentrations to prevent BO from searching for infeasible solutions. Initially designed for chemical reactions, the versatile barycentric kernel shows promising potential for a wide range of optimization problems, including those requiring a meaningful distance metric between mixtures. [ABSTRACT FROM AUTHOR]

In this paper, we consider the prediction of the helium concentrations as function of a spatially variable source term perturbed by fractional Brownian motion. For the direct problem, we show that it is well-posed and has a unique mild solution under some conditions. For the inverse problem, the uniqueness and the instability are given. In the meanwhile, we determine the statistical properties of the source from the expectation and covariance of the final-time data u (r , T). Finally, numerical implements are given to verify the effectiveness of the proposed reconstruction. [ABSTRACT FROM AUTHOR]

When a fiber break occurs in longitudinal tension of a unidirectional composite, dynamic stress concentrations arise, which can be different from the ones found considering only static loading. The current paper analyzes the dynamic stress concentration factors (SCF) around a fiber break in unidirectional carbon fiber/epoxy composites. 3D finite element models with random and hexagonal fiber distributions were analyzed to investigate the evolution of stress concentrations as a function of time and position. The results indicate that dynamic effects result in much higher SCFs with a larger effective area around the broken fiber. The increase of SCFs in the closest fibers was determined to be larger for lower fiber volume fractions due to the presence of dynamic effects. Similar to the static case, a lower volume fraction causes higher maximum dynamic SCF in random packings. Results also support the high prevalence of coplanar cluster breaks observed in the experiments. [ABSTRACT FROM AUTHOR]

Experiments are routinely conducted to evaluate the toxicity of water effluents or chemicals. In a Ceriodaphnia dubia reproduction test, organisms are exposed to varying concentration levels of the toxicant or other adverse treatment and the number of young produced after a given experiment period are recorded. To analyze the test outcomes, mean reproduction is modeled as a function of the concentration, and the estimated concentrations associated with specified levels of adverse effect often are used in risk management. While aquatic toxicity analyses often focus on outcomes from the current test, laboratories commonly have a history of conducting such tests using the same species, following a similar experimental protocol. So it seems reasonable to assume that the same underlying biological process generates the historical and current tests. In the present study, we propose using a calibrated power prior approach to incorporate historical control outcomes as prior input, and compare the behavior of the method when different congruence measures are used to determine the amount of historical input that will be incorporated. Simulation results show that three of the congruence measures can improve precision and reduce bias of the potency estimates.Supplementary material to this paper is provided online. [ABSTRACT FROM AUTHOR]

Let X$X$ be a random variable and define its concentration function by Qh(X)=supx∈RP(X∈(x,x+h]).$$\begin{equation*} {\mathcal {Q}}_{h}(X)=\sup _{x\in {\mathbb {R}}}{\mathbb {P}}(X\in (x,x+h]). \end{equation*}$$For a sum Sn=X1+⋯+Xn$S_n=X_1+\cdots +X_n$ of independent real‐valued random variables, the Kolmogorov–Rogozin inequality states that Qh(Sn)⩽C∑i=1n(1−Qh(Xi))−12.$$\begin{equation*} {\mathcal {Q}}_{h}(S_n)\leqslant C{\left(\sum _{i=1}^{n}(1-{\mathcal {Q}}_{h}(X_i))\right)}^{-\frac{1}{2}}. \end{equation*}$$In this paper, we give an optimal bound for Qh(Sn)${\mathcal {Q}}_{h}(S_n)$ in terms of Qh(Xi)${\mathcal {Q}}_{h}(X_i)$, which settles a question posed by Leader and Radcliffe in 1994. Moreover, we show that the extremal distributions are mixtures of two uniform distributions each lying on an arithmetic progression. [ABSTRACT FROM AUTHOR]

Cr3+‐activated broadband near‐infrared (NIR) phosphors are studied extensively for application in phosphor converted light‐emitting diode (pc‐LED), a new light source for substance testing based on NIR spectroscopy. However, the emission of Cr3+ is mainly located in the NIR I region (700–1000 nm) and many substances show the characteristic spectroscopy in the NIR II region (1000–1700 nm). In this paper, dual‐wavelength emission of NIR I and NIR II is realized in Cr3+ and Ni2+ codoped Zn3Ga2GeO8 (ZGGO) via energy transfer from NIR I emitting Cr3+ to NIR II emitting Ni2+. The photoluminescent properties of the doped ZGGO are studied as a function of doping concentration and the optimal concentrations of Cr3+ and Ni2+ are determined to be 0.04 and 0.003, respectively, with internal quantum efficiency (IQE) of 37.5%. The ZGGO:Cr3+, Ni2+ phosphor‐in‐glass (PiG), is prepared for fabricating PiG‐converted ultrabroadband NIR LEDs to avoid serious reabsorption of the NIR II emission as in the pc‐LED packaged using phosphor dispersed epoxy resin or silicone. The PiG pc‐LED offers photoelectric efficiency of 4.3%@20 mA and NIR output power of 17 mW@200 mA and shows stable spectral distribution against drive current compared to pc‐LED. [ABSTRACT FROM AUTHOR]

The incorporation of oppositely charged polyelectrolytes into a block copolymer system can lead to formation of microphase separated nanostructures driven by the electrostatic complex between two oppositely charged blocks. It is a theoretical challenge to build an appropriate model to handle such coacervate-driven self-assembly, which should capture the strong electrostatic correlations for highly charged polymers. In this paper, we develop the self-consistent field theory considering the ion paring effect to predict the phase behavior of block polyelectrolytes. In our model, two types of ion pairs, the binding between two oppositely charged monomers and the binding between charged monomers and counterions, are included. Their strength of formation is controlled by two parameters Kaa and Kac, respectively. We give a detailed analysis about how the binding strength Kac and Kaa and salt concentration affect the self-assembled nanostructure of diblock polyelectrolyte systems. The results show that the binding between two oppositely charged blocks provides driven force for microphase separation, while the binding between charged monomers and counterions competes with the polyion pairing and thus suppresses the microphase separation. The addition of salt has a shielding effect on the charges of polymers, which is a disadvantage to microphase separation. The phase diagrams as a function of polymer concentration and salt concentration at different situations are constructed, and the influence of Kaa, Kac, and charged block composition fa is analyzed in depth. The obtained phase diagrams are in good agreement with currently existing experimental and theoretical results. [ABSTRACT FROM AUTHOR]

The article presents a study on the evaluation and implementation of the sectional aerosol microphysics model SALSA within the aerosol-climate model ECHAM5-HAM. It mentions that the said module has been made to be flexible and effective in computations towards its enforcement in regional and global scale models. It also notes an assessment of its ability to describe global aerosol properties in comparisons against measured size distribution, sea salt mass concentrations and budgets.

Inhibiting a signalling pathway concerns controlling the cellular processes of a cancer cell's viability, cell division and death. Assay protocols created to see if the molecular structures of the drugs being tested have the desired inhibition qualities often show great variability across experiments, and it is imperative to diminish the effects of such variability while inferences are drawn. In this paper, we propose the study of experimental data through the lenses of a mathematical model depicting the inhibition mechanism and the activation-inhibition dynamics. The method is exemplified through assay data obtained from an experimental study of the inhibition of the chemokine receptor 4 (CXCR4) and chemokine ligand 12 (CXCL12) signalling pathway of melanoma cells. The quantitative analysis is conducted as a two step process: (i) deriving theoretically from the model the cell viability as a function of time depending on several parameters; (ii) estimating the values of the parameters by using the experimental data. The cell viability is obtained as a function of concentration of the inhibitor and time, thus providing a comprehensive characterization of the potential therapeutic effect of the considered inhibitor, e.g. |$IC_{50}$| can be computed for any time point. [ABSTRACT FROM AUTHOR]

This paper contributes to the post‐Keynesian literature by building a macrodynamic Kaleckian model that incorporates recent evidence on market concentration and its relationship with capital accumulation and income distribution using Schumpeterian insights. This is done in two steps. First, we model a two‐dimensional system that sets the dynamics between the wage share and the capital‐effective labor supply ratio. Then, we extend the model, in the second step, to a three‐dimensional system that incorporates the state‐transition function of concentration. Our model suggests that higher market concentration may be associated with a permanent decline in employment, capacity utilization, wage share, and capital accumulation. [ABSTRACT FROM AUTHOR]

In part I of this paper series, the application of an incomplete adjoint operator to calculate the optimal reduction of the total emissions S′ was suggested. This paper, part II of the series, focuses on calculating the reduction of the anthropogenic emission source S′a As Sc (the source term due to the chemical reaction in the atmosphere) is a complex function of the pollutant concentration ρ, we propose an iterative optimization method using a positive-negative discriminant to obtain S′a from S′. The convergence of the iterations is also proven in this paper. [ABSTRACT FROM AUTHOR]

This paper discusses the results of high temperature resistivity and Hall effect studies of Mg-doped GaN and AlxGa1−xN epilayers (0.05 < x < 0.23). The studied samples were grown by molecular beam epitaxy on low temperature buffers of GaN and AlN deposited on a sapphire substrate. The experiments were carried out at temperatures ranging from 300 up to 1000 K. Up to a certain critical temperature TC (around 800 K), a typical increase of the conduction processes due to the excitation of impurity states has been observed with an activation energy of about EA = 200 meV. However, at this critical temperature TC, an annealing effect was observed in all the investigated samples. At this critical temperature, the increase in the free carrier concentration as a function of time leads to an irreversible decrease in the samples' resistivity of more than 60%. The observed temperature dependences of the electrical transport properties are analyzed in the frame of an impurity model including shallow donors and Mg-related acceptors (with EA ∼ 200 meV). In some cases, an additional conduction channel not related to free carriers in the valence band must be taken into account. This can lead to an incorrect determination of hole concentration in the valence band, an important parameter in the process of radiative recombination. [ABSTRACT FROM AUTHOR]

PDY-132 and its blends with different concentrations of poly(9,9-dioctylfluorenyl-co-3 bithiophene) F8T2 were employed as an emissive matrix for organic light-emitting devices (OLEDs). The Urbach energy lies well below 50 meV, which reflects the reduced energetic disorder, signifying the efficient charge transfer in the polymer blends. The photoluminescence time constants vary proportionally from 0.89–0.35 ns as a function of the acceptor concentration in the FRET pairs, reflecting 2.5× faster charge transfer in the blends than in PDY-132. The Förster radius of 57 Å, decay time of 0.89 ns, quenching constant of 0.12 μM−1, quenching rate constant of 1.4 × 108 μM−1 s−1, charge transfer lifetime of 6.21 ns to 2.38 ns, and non-radiative transfer rate of 4.0 × 108 s−1 exhibit the excellent parameters for efficient charge transfer within the blend, resulting in lowering of the turn on voltage by 67% from 6.5 V to 2 V. The current density of 3 mA cm−2 increases to 25 mA cm−2, an increase of 8× with increasing concentration of F8T2. [ABSTRACT FROM AUTHOR]

This paper aims to establish distribution-free concentration inequalities for the log-likelihood function of Bernoulli variables, which means that the tail bounds are independent of the parameters. Moreover, Bernstein's and Bennett's inequalities with optimal constants are obtained. The simulation study shows significant improvements over the previous results. [ABSTRACT FROM AUTHOR]

This paper focuses on a fractional crystallization methodology using a rotating and internally gas-cooled crystallizer to purity crude selenium. Experiments using a rotating and gas-cooled crystallizer (cooled finger) were performed. The distribution coefficients of the main impurities (Pb, Fe and Hg) in selenium were presented as a polynomial function of concentration. The experimental parameters such as crystallization temperature and rotation rate were determined and discussed. The appropriate crystallization temperature is 222 °C and the rotation rates are 120 and 300 rpm, respectively. The purity of crude selenium increased from 99.9% to over 99.997%. Compared with the traditional method such as zone melting, this method only takes less than one day to complete several purifications, and the purification effect is better than the former. The removal rates of Hg, Pb and Fe in Se are 28.70%, 97.63% and 96.28%, respectively. The direct yield of Se purified is 92.5%. This study provides an efficient process for high-purity selenium, which has important industrial applications. [ABSTRACT FROM AUTHOR]

Cell metabolite detection is important for cell analysis. As a cellular metabolite, lactate and its detection play an important role in disease diagnosis, drug screening and clinical therapeutics. This paper reports a microfluidic chip integrated with a backflow prevention channel for cell culture and lactate detection. It can effectively realize the upstream and downstream separation of the culture chamber and the detection zone, and prevent the pollution of cells caused by the potential backflow of reagent and buffer solutions. Due to such a separation, it is possible to analyze the lactate concentration in the flow process without contamination of cells. With the information of residence time distribution of the microchannel networks and the detected time signal in the detection chamber, it is possible to calculate the lactate concentration as a function of time using the de-convolution method. We have further demonstrated the suitability of this detection method by measuring lactate production in human umbilical vein endothelial cells (HUVEC). The microfluidic chip presented here shows good stability in metabolite quick detection and can work continuously for more than a few days. It sheds new insights into pollution-free and high-sensitivity cell metabolism detection, showing broad application prospects in cell analysis, drug screening and disease diagnosis. [ABSTRACT FROM AUTHOR]

Economic activity is highly unevenly distributed within cities, as reflected in the concentration of economic functions in specific locations, such as finance in the Square Mile in London. The extent to which this concentration reflects natural advantages versus agglomeration forces is central to a range of public policy issues, including the impact of local taxation and transport infrastructure improvements. This paper reviews recent quantitative urban models, which incorporate both differences in natural advantages and agglomeration forces, and can be taken directly to observed data on cities. We show that these models can be used to estimate the strength of agglomeration forces and evaluate the impact of transportation infrastructure improvements on welfare and the spatial distribution of economic activity. [ABSTRACT FROM AUTHOR]

This paper describes the current state of the initiation of the global spontaneous fires and the reasons of their apparitions. Their spontaneity probably is related to the presence of the pollutants in the atmosphere such as methane and fuel particles. Moreover, methane is the precursor of ozone. Ozone, in its turn, is the factor that leads to the destruction of flora and the transformation of flora into the fuel. It is also clear that the complex processes that take place in the Biosphere with the presence of polluting gases and the occurrence of fires lead to the development of the states of extreme temperature variations, drought and floods. Increasing albedo values have an increasing influence on the development of extreme temperatures and other natural cataclysms. An empirical method based on the thermodynamic laws of ignition point with fire cascade processes is elaborated. The empirical expression of the albedo variation as the function of concentration of green house gas also is elaborated and suggested. [ABSTRACT FROM AUTHOR]

The main aim of the present paper is to characterize the hydration properties of glucose and the hydrogen bond network in glucose–water mixtures. For these purposes, temperature scans on ten concentration values of glucose–water mixtures were performed by means of Fourier Transform InfraRed (FTIR) spectroscopy. More specifically, in order to get this information an analysis of the intramolecular OH stretching mode, investigating the 3000–3700 cm−1 spectral range, was performed by means of an innovative approach based on the evaluation of the Spectral Distance (SD). The adopted procedure allows evaluating the glucose hydration number as well as characterizing the temperature behavior of the hydrogen bond network in the glucose–water mixtures. The obtained results for the hydration number are in excellent agreement with literature data and suggest the existence of a particular concentration value for which the hydrogen bond network shows a maximum strength. [ABSTRACT FROM AUTHOR]

This paper addresses the impact of the particle initial wetting and the viscosity of the oil phase on the structure and rheological properties of direct (Oil/Water) and reverse (Water/Oil) Pickering emulsions. The emulsion structure was investigated via confocal microscopy and static light scattering. The flow and viscoelastic properties were probed by a stress-controlled rheometer. Partially hydrophobic silica particles have been employed at 1 and 4 wt.% to stabilize dodecane or paraffin-based emulsions at 20 vol.% of the dispersed phase. W/O emulsions were obtained when the particles were dispersed in the oily phase while O/W emulsions were prepared when the silica was introduced in the aqueous phase. We demonstrated that, although the particles adsorbed at the droplets interfaces for all the emulsions, their organization, the emulsion structure and their rheological properties depend in which phase they were previously dispersed in. We discuss these features as a function of the particle concentration and the oil viscosity. [ABSTRACT FROM AUTHOR]

In this paper, via variational methods, we consider the existence and concentration of positive solutions for a system of Schrödinger-Poisson equation involving concave-convex nonlinearities under some suitable assumptions of weight functions. [ABSTRACT FROM AUTHOR]

In this paper we study uniformly random lozenge tilings of strip domains. Under the assumption that the limiting arctic boundary has at most one cusp, we prove a nearly optimal concentration estimate for the tiling height functions and arctic boundaries on such domains: with overwhelming probability the tiling height function is within n δ of its limit shape, and the tiling arctic boundary is within n 1 / 3 + δ to its limit shape, for arbitrarily small δ > 0 . This concentration result will be used in Aggarwal and Huang (Edge statistics for lozenge tilings of polygons, II: Airy line ensemble, 2021. arXiv:2108.12874) to prove that the edge statistics of simply-connected polygonal domains, subject to a technical assumption on their limit shape, converge to the Airy line ensemble. [ABSTRACT FROM AUTHOR]

This paper presents a detailed analysis of the optical performance of circular trough concentrators with tubular receivers. First, a simple analytical formula for the achievable geometric concentration ratio as a function of the rim angle and acceptance angle is developed. Notably, the development reveals the existence of three distinct concentration ratio regimes: a first regime where the receiver is sized based on the reflection of the edge rays from the rim alone, a second regime where the receiver is sized based on the rim and the edge ray caustics, and a third regime where two reflections from the mirror are permitted. Several exemplary designs are proposed and further analyzed using Monte Carlo ray tracing to obtain transmission angle curves and receiver flux distributions. For an acceptance angle of 1 deg, the circular trough concentrator with circular receiver is found to achieve a maximum geometric concentration ratio of 7.695× with a peak flux of 30 suns. For large acceptance angles (10 deg), the circular trough achieves a geometric concentration ratio as high as 82% of that of a parabolic trough. This noteworthy performance, along with the fact that a circular mirror is amenable to an inflated polymer construction, makes this configuration promising for low-cost, low-concentration solar thermal applications. [ABSTRACT FROM AUTHOR]

In this paper, the actual background of the susceptible population being directly patients after inhaling a certain amount of PM 2.5 is taken into account. The concentration response function of PM 2.5 is introduced, and the SISP respiratory disease model is proposed. Qualitative theoretical analysis proves that the existence, local stability and global stability of the equilibria are all related to the daily emission P 0 of PM 2.5 and PM 2.5 pathogenic threshold K. Based on the sensitivity factor analysis and time-varying sensitivity analysis of parameters on the number of patients, it is found that the conversion rate β and the inhalation rate η has the largest positive correlation. The cure rate γ of infected persons has the greatest negative correlation on the number of patients. The control strategy formulated by the analysis results of optimal control theory is as follows: The first step is to improve the clearance rate of PM 2.5 by reducing the PM 2.5 emissions and increasing the intensity of dust removal. Moreover, such removal work must be maintained for a long time. The second step is to improve the cure rate of patients by being treated in time. After that, people should be reminded to wear masks and go out less so as to reduce the conversion rate of susceptible people becoming patients. [ABSTRACT FROM AUTHOR]

Summary: In this article, MXene nano‐material is used with silicone oil to improve the thermal conductivity of nano‐fluids and it further increases the heat transfer. MXene nano‐material‐silicone oil‐based nano‐fluids have the capacity to be employed as heat transfer fluids in various thermal applications since it has excellent thermal properties, higher heat resistance and silicone oil have the ability to operate upto a temperature of 400°C. This paper investigates the thermal conductivity values for different concentrations and temperature of MXene nano‐fluids. The thermal conductivity of the prepared MXene nano‐fluids is strongly dependent on temperature and concentration of MXene nano‐particles. The values of thermal conductivity are predicted by developing multilayer perceptron (MLP) Artificial Neural Network (ANN) model. The temperature and nano‐particles concentration are taken as inputs and thermal conductivity is taken as output to the model. Mean square error (MSE) and correlation coefficient (R) are used to assess the efficacy of the developed model using trial and error method. The values of MSE and correlation coefficient for the optimum model are found to be 2.6 × 10−07 and 0.99687, respectively. A correlation for thermal conductivity as a function of temperature and concentration is also propounded using the experimental results. The developed optimum ANN model show satisfactory performance, and the predicted thermal conductivity values matches well with experimental thermal conductivity values. [ABSTRACT FROM AUTHOR]

Background: Simple isotherm models, such as the Langmuir and Freundlich equations, are frequently used to correlate water contaminant adsorption data. In the conventional data fitting approach, the Langmuir and Freundlich equations are fitted to experimental data by minimizing the difference between the measured and calculated adsorbed phase concentrations. However, some isotherm equations are implicit in adsorbed phase concentration. Such isotherms must be converted to explicit forms to allow the use of standard nonlinear regression methods in data correlation. This paper explores the use of the Lambert W function to invert the loading‐implicit isotherms of Elovich, Volmer, and Jossens to solve for adsorbed phase concentration as a function of liquid phase concentration. Results: The inverted Elovich, Volmer, and Jossens isotherms were fitted to literature adsorption data of water contaminants using the standard nonlinear regression procedure in Excel. Data fitting was accomplished by making use of a freely available Excel add‐in and a highly accurate analytical approximation to evaluate the Lambert W function. The inverted isotherms were tested against the experimental isotherms of cobalt, uranium, and cephalosporin C. In all cases studied, satisfactory fits were obtained, validating the practicability of the proposed data fitting approach. Conclusions: The loading‐implicit Elovich, Volmer, and Jossens isotherms can be formulated as loading‐explicit equations in terms of the Lambert W function, thus allowing the use of conventional least‐squares fitting procedures in data correlation. The practical implementation of the Lambert W function in Excel provides a novel method to fit loading‐implicit isotherms to experimental data of water contaminants. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

An Al/JP-10/oleic acid nanofluid fuel system has demonstrated potential in advanced combustion for aviation turbine engines. To improve the energy density of nanofluid fuel, a higher Al concentration requirement needs to be met. Correspondingly, a higher surfactant oleic acid concentration is required to maintain better dispersion stability. The increment of Al and oleic acid concentrations results in more frequent microexplosions, but a slower evaporation rate. Therefore, this paper proposes to deeply understand the contradiction of the concentration effect on the stability, physical properties, evaporation and microexplosion characteristics and obtain the best Al and oleic acid concentrations to maintain the most suitable comprehensive performance. Experiments on the stability, physical properties, evaporation and microexplosion characteristics were conducted, respectively. The analysis and discussion were then made to reveal the Al and oleic acid concentration effect on the stability, physical properties, evaporation and microexplosion characteristics. The results show that the optimum mass ratio of Al:oleic acid is 1:2 for the nanofluid fuels with Al concentrations of 2.5 wt.% or below, 1:2.5 for 5.0 wt.% or above to obtain the best stability. The physical properties of the nanofluid fuels such as density, surface tension and viscosity are linear, quartic and quadratic functions of Al concentration, respectively, relating to the internal flow and microexplosion of fuel droplets. With increasing oleic acid and Al concentration, the evaporation rates reduced, and the microexplosions became more frequent and intense. At a high ambient temperature of 600 °C, the evaporation rates were kept almost equivalent for JP-10, JP-10/oleic acid, and Al/JP-10/oleic acid fuels. It was found that the increment of ambient temperature can compensate for the reduction of the evaporation rate owing to the addition of oleic acid and Al nanoparticles, improving the evaporation and microexplosion performance. [ABSTRACT FROM AUTHOR]

In aquatic toxicity tests, responses of interest from organisms exposed to varying concentration levels of the toxicant or other adverse treatment are recorded. These responses are modeled as functions of the concentration and the concentration associated with specified levels of estimated adverse effect are used in risk management. While aquatic toxicity analyses often focus on outcomes from a single experiment, laboratories commonly have a history of conducting such experiments using the same species, following a similar experimental protocol. So it is often reasonable to believe that the same underlying biological process generates the historical and current experiments. This connection may facilitate the design of more efficient experiments. In the present study, we propose a simulation-based Bayesian sample size determination approach using historical control outcomes as prior input and illustrate it using a C. dubia reproduction experiment with count outcomes. Simulation results show that precision of the potency estimates is improved via incorporation of historical data. For a standard EPA required test of 60 total organisms, when a single historical control study is incorporated assuming moderate relevance, the mean length (AL) of the 95 % interval of RI 25 (the concentration associated with 25 % inhibition relative to control) is reduced by 17 % . So more precision is possible from the historical control data or a reduction of 40 % of the 60 organism would result in the same precision for a pre-specified AL criterion. The incorporation of multiple historical controls assuming moderate relevance would reduce AL by 37 % , translating into a reduction of 70 % of the current default sample size. Supplementary materials accompanying this paper appear online. [ABSTRACT FROM AUTHOR]

This paper synthesises insights and offers new quantitative analyses of data gathered during 40 years of stream research by Danish researchers and international associates. Lowland Danish streams mostly drain fertile cropland and contain high nutrient concentrations saturating maximum yield and growth rate of plants. Concentrations of carbon dioxide (CO2) are variable, although usually high, supporting a range of wetland and permanently submerged species.All terrestrial and most amphibious species are obligate CO2 users, while the majority of permanently submerged species can supplement their inorganic carbon demand with bicarbonate. In lake outlets, the average CO2 concentration was close to air saturation during summer, whereas sites with no lake influence were 9‐fold supersaturated. The 20% increase of atmospheric CO2 concentrations over the past 40 years has marginal influence on CO2 concentrations in the streams.In lake outlets with low CO2 concentrations, calculations on 33 stream species showed essentially no underwater photosynthesis by temporarily submerged terrestrial species, low rates by amphibious species, and high rates by permanently submerged bicarbonate users. Underwater photosynthetic rates increased at sites with high CO2 concentrations (no lake influence): they were lowest for terrestrial wetland species (mean 1.8 mg O2 g dry weight−1 hr−1), followed by homophyllous (3.0) and heterophyllous amphibious species (5.6), and highest among permanently submerged species (15.0). Terrestrial and amphibious species grew very slowly when CO2 levels were low, but rapidly in CO2 rich water, or when in contact with air above the water's surface. Decreasing CO2 concentrations from upstream to downstream caused lower photosynthesis rates of amphibious species, while photosynthesis by bicarbonate users was consistently high.The relative abundance of terrestrial and amphibious species decreased significantly as CO2 resources decline from upstream to downstream, while the abundance of permanently submerged species increased as streams progressed. However, plant abundance as a function of CO2 concentrations did not differ markedly among the plant groups.We conclude that photosynthesis and growth of species of different plant types under controlled experimental conditions resembling high in situ nutrient availability are closely related to inorganic carbon supplies, while their representation in plant assemblages is influenced by the spatially and temporally highly diverse ecological conditions from upstream to downstream in the mostly CO2‐rich lowland streams.Submerged terrestrial and amphibious species restricted to CO2 use for photosynthesis can partly escape the slow gas diffusion under water by growing in very CO2‐rich streams and having apical leaves in contact with air. Thus, strong restrictions on their growth and existence should be identified at sites where CO2 concentrations are consistently low and no air contact is possible, while co‐limitation by nutrients is likely to be marginal.Generally, rising atmospheric CO2 is irrelevant to photosynthesis of permanently submerged plants because of their ability to use bicarbonate and the high CO2 supersaturation in most stream sites. In contrast, photosynthesis and growth of amphibious and terrestrial plants under water are highly dependent on CO2 concentrations varying from close to air saturation in lake outlets to supersaturation in headwaters. [ABSTRACT FROM AUTHOR]

Post-operative neurocognitive disorders are becoming well-documented conditions, with their pathogenesis remaining unclear. Vitamin C is a molecule that has recently demonstrated both a potential link with cognitive function and a significant post-operative decline. Here, we present a case study of a 72-year-old male who underwent total knee replacement surgery. The patient demonstrated a substantial decline in plasma vitamin C concentrations, indicative of a severe deficiency, during the first post-operative week (post-operative Days 3 and 7). Similarly, at these time points, a number of validated paper and pen tests revealed a substantial decline in cognition on tasks relating to total recall, delayed recall, motor speed, recognition and motor speed, with no signs of delirium. These results provide the justification for larger, cohort studies to determine whether post-operative plasma vitamin C depletions could contribute to cognitive deficits post-operatively. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to study the process of coprecipitation of polyhydroxocomplexes of nickel and aluminum from solutions of nickel (Ni) (II) sulfate and aluminum (Al) (III) sulfate with caustic soda and to study the conversion process to nickel aluminate and to check its properties. Design/methodology/approach: For the thermodynamic analysis of the precipitation process, the software package MEDUSA was used. The dependences of the electrical conductivity, pH and residual concentrations as functions of the OH/Me ratio were obtained. Using X-ray phase analysis, spectroscopic analysis and derivatographic analysis, the properties of the products obtained were studied. The effects of OH/Me ratio and molar ratio cation of reagents on the physicochemical properties of the products were analyzed. Findings: The paper deals with the results of theoretical and experimental research on the synthesis pigments of blue and green colors based on Ni-Al spinel. The influence of the molar ratio cation content on optical and color characterise of pigments were studied. Originality/value: The original complex method of studying the processes of co-precipitation of cations in the form of hydroxides is proposed. pH precipitation of aluminum hydroxide and nickel are different. It is interesting to study their co-precipitation. The resulting single-phase product is a precursor of nickel aluminate over a wide range of cation ratios. The dependences of the electrical conductivity, pH and residual concentrations as functions of the OH/Me ratio were obtained. [ABSTRACT FROM AUTHOR]

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The paper deals with studying a connection of the Littlewood–Offord problem with estimating the concentration functions of some symmetric infinitely divisible distributions. It is shown that the concentration function of a weighted sum of independent identically distributed random variables is estimated in terms of the concentration function of a symmetric infinitely divisible distribution whose spectral measure is concentrated on the set of plus-minus weights. [ABSTRACT FROM AUTHOR]

Vitamin C (ascorbic acid, AA) is a weak sugar acid structurally related to glucose. All known physiological and biochemical functions of AA are due to its action as an electron donor. Ascorbate readily undergoes pH-dependent autoxidation creating hydrogen peroxide (H2O2). In vitro evidence suggests that vitamin C functions at low concentrations as an antioxidant while high concentration is pro-oxidant. Thus, both characters of AA might be translated into clinical benefits. In vitro obtained results and murine experiments consequently prove the cytotoxic effect of AA on cancer cells, but current clinical evidence for high-dose intravenous (i.v.) vitamin C's therapeutic effect is ambiguous. The difference might be caused by the missing knowledge of AA's actions. In the literature, there are many publications regarding vitamin C and cancer. Review papers of systematic analysis of human interventional and observational studies assessing i.v. AA for cancer patients' use helps the overview of the extensive literature. Based on the results of four review articles and the Cancer Information Summary of the National Cancer Institute's results, we analyzed 20 publications related to high-dose intravenous vitamin C therapy (HAAT). The analyzed results indicate that HAAT might be a useful cancer-treating tool in certain circumstances. The AA's cytotoxic effect is hypoxia-induced factor dependent. It impacts only the anoxic cells, using the Warburg metabolism. It prevents tumor growth. Accordingly, discontinuation of treatment leads to repeated expansion of the tumor. We believe that the clinical use of HAAT in cancer treatment should be reassessed. The accumulation of more study results on HAAT is desperately needed. [ABSTRACT FROM AUTHOR]